Gas fueled pilot burner and ion sensing flame probe



J. W. SMITH Filed Dc. 22, 1949 24. lla.

GAS FUELED PILOT BURNER AND ION SENSING FLAME PROBE Ila- Feb. '2,' 1954 nuentor JAMES W. SMITH Gttorneg Patented Feb. 2, 1954 "Minneapolis-Honeywell Regulator ""Company, yrltiimreapolis,"Minn.; a corporation f'D'eIaWare /ApplicationLDecemhen 22, 1949.; Serial No`1-34^366 En #STATES moi-E lvl'I'hiseinvention relates to igniting devices .of the type.which-.comprises a .pi1ot..burner, .'for igniting` a. muchlarger main burner, along. with electricalfmeans forgigniting the `pilotlourner and forK detecting the. presence yor. absence of. a flame at. 'thecpilotV burner.

Igniting devices of- .the .above mentioned type are `Well known in the @heating art and, particularly, lin heating systems which i use. gas 1f as fuel. In.these A systems suitablecontrol means, suohes aroomtthermostat,:causes the oW-ofgasto the pilot burnerl andftheiiow. of electrical energvto an,igniter.,for.said pilot..burner, lWhenever there is a demand for heat. In order to prevent the main y burner from Ystarting .up immediate1y, regardlessvofl whether onnot .there is fa flame at thepi1ot .burner 4lforieniting-.the .main burner, aflamef sensing means usually has been` supplied which will fcause the valvecontrolling .the .gas flow to the .mainmburner tofopenonly ifa ame present at '.the-pi1otmburner- Otherwise, the main @burner remainsnclosed, or, .if the-.main burner. -hasfcome :onA and the-pilot .burner subsequentlyfbecornes :extinguished themain burner will be shut-rofl'.

l. Onefof the objects.ofthisfinvention isto provide :an .igniting tdevice: :of 1 thev above mentioned type `which-is compact-.anddnexpensivefyet sturdy infcons-truction :and reliable' in operation.

:Another obj ectfof the: invention L-is toprovide ani-igniting cdevice .of the .type .described wherein the orifice construction of the burner prov-ideale divided flame,r vonefor self 'ignition andi the other ioriigniting-.1a-fmain burner and yfor cooperating with the f'ame sensing'element of-l the igniter device.

Still another object of the. invention-iste `proburner, construction,-` Wherein a shield is provided for vpreventing the ,.fame .for ignitng the; pilot burner iirom contacting V; theA flame sensing Lele mente exposed` to the otherflame for .igni-ting f a main zburner.

A still further object of :the Yinventionffis. to provideran' igniting idevioehaving-.a divided; flame burnenza spark ignitenafame sensingelectrode, ancha shield;forgrounding'ionszgenerated lbyxsaid spark :igniter and thus i 'preventing wthern from reaching` .theffame "sensing electrode.

Another objectzof the'invention is 12o/provide an-:ignting device. havingza 'simple and 'compact arrangement "whereby .an :electrical rwigniting means. for. the ,pilotzburner'zmayrbe I on the-same side-.foffaand'closelyspaced fromlanother electrical means;V for-'.-fsensingttheefpresence of a v."fl'ame'a o the .pilot.. burner.

Othenobjectsof-,theinvention will beeomeiapparent Mupon readingl the followingy detailed... descriptionn of .theHinventioniin conjunction vv'with the accompanying. drawing wherein:

ligure .1= istaside.elevational view of theignitingodevice;

Figure 2 .islam-:elevational: end lview .of .the device;-.and

.Figure 3. is la planwviewfofsthe Tigniting device with portions thereof. :broken-awayl Inrthetdrawingfthereference numeral I I .designates .a .pilotrburner-fbody Seeured ,to `the upper-.endfof the body II .is a` cup-shaped: burner tip-I2 .having a .coaxial {orifice-Beintithe-.end thereof, .aairadially-.extending orifice I4in--..the side .vthereof; ,andY a runner slotf-I 5 extending.-.be tween said-oriices'and;diarnetrieally through the said Yend. ...Allower .portion I-Ia of the body II is: -of.s1ight1y;f,.greater :thickness-than the upper portion, `and ist oef-1V hexagonal .-shape. A11-upper partof. thecpontion 1 I Iaxhas the. corners tof the adjoining fsidestbeveledl orf'. ati-1I B- =to-form= sho-ulders y I 'I .fattthedowerffend of 'the :beveledfportion Therlower, fendffoff thebodyportion IfI affisv internally threaded (notfshown) `to -receiveaconventionalburnenspud IB. ,Theispud clampsvafshield I9: inpposition :aroundthe-flower end :portion of the burner to protect a primarynairopeningfZI) of. thehurner fromfsanzenveiopingfllame,,:should one occur. :I'Iheidetailsoi-Ythis; primary't-air shield form nogpartof .thisinrentionibut arefullydisclosedein fagzcopendingffapplicationeofl George JenkinsfrSerialzffNo. .=-135,623,.fled ;.Beoember f 129, 19.49 fowned?. bywthe `x'assignee of this application.

;A bracket-xv 2 I ,.--formed:.-r of asheet metal, uhas a longe sidewzalleZL-nan upperwall-23A and slower Wall.M2Ifsoffzequalv lengthtorthe side wall- Maand a: sideffwall.: 25 'of shortertflength than -1Wal1v2-2. Apertured ears'l: formounting'theabracketmemloert to; aesuitable supporteextendwlaterally from isralsofwap'er15u-redl son a slotted at its f outer-tendras anys! suitable'fmateriahep referablyea. :ceramionna terial, and the free end thereof engaged by a conventional lead wire connector 33. The sleeve 32 has a longitudinally extending rib 34 substantially in alignment with the short leg of the electrode 3|. The sleeve 32 bears against an arcuate-shaped recess 35 formed in the upper wall 23 and lower wall 24 of the bracket, with the rib 34 bearing against shoulders 36 formed on said walls. It is thus seen that when the sleeve member 32 is held in this position, the short leg of the electrode 3| will be held in alignment with the orifice I4. To hold the sleeve 32 and the short leg of electrode 3| in position longitudinally of the burner, a clamping plate 31 is provided, having two arcuate portions 38 and 39 and two ears 4I) and 4| extending from the ends of the arcuate portions 38 and 39 respectively. The clamping plate issecured to the bracket 2| by means of the screw 30, described above, with the arcuate portion 38 clamping the sleeve 32 and the ear 4I! engaging in a notch 34a in the rib 34. As the electrode 3| is rigidly secured to the sleeve 32, it is apparent that the electrode 3| will be held in a position which will permit a flame of the orifice I4 to impinge on at least the outer end of the short leg. The distance of the end of the short leg from the orifice I4 should be 1% of an inch for the best operation of the igniting device.

An L-shaped, flame-sensing electrode 42 is likewise surrounded by and rigidly secured to an insulation sleeve 43, substantially the same as sleeve 32. This sleeve 43 has a longitudinally extending rib 44 on the opposite side of the sleeve from the short leg of electrode V42 but in the same plane thereof. 'Ihe sleeve 43 is clamped to the bracket 2|, in recesses 45 in the upper wall 23 and lower wall 24 by the arcuate portion 39 of clamping plate 31. As in the mounting of the electrode 3|, the ear 4I engages in a notch 44a in the rib 44 to hold the electrode 42 in longitudinal adjustment. The rib 44 bears against abutment shoulders 46 in said walls to prevent rotation of the sleeve 43 and thus hold the outer end of the short leg of the electrode 42 in position to be contacted by a flame issuing from the orifice I3.

Mounted on the burner tip I2 by means of screw I 2a, the same screw that holds the tip I2 on burner II, is an electrode shield 41. The shield has a flat wall portion 48 which lies in a plane at right angles to the plane of the short legs of the electrodes 3| and 42 with substantially the central portion thereof positioned in the plane of said electrodes and with one end thereof substantially on a line extending from orifice I3 to the outer end of the short leg of electrode 42. The other end of the wall 48 is integral with or connected to a wall 49 which extends downwardly between the electrodes 3| and 42 in a plane at right angles to the plane of electrodes 3| and 42. The lower end of this wall 49 terminates at a point slightly inwardly of the upper ends of the sleeves 32 and 43, as viewed in Figure l of the drawing. An arcuate portion 41a of the shield member 41, being tightly held against an arcuate surface of the burner tip I2, by the screw I2a, prevents pivoting of the shield member 41 around the screw I2a and thus holds the shield rigidly in position.

Operation The above described igniting device is intended 4 3, at the end of the ame sensing electrode 42, is in the path of a portion of the gas flowing from a main burner (not shown) of the furnace of a heating system. The electrode 3| should be connected to a source of highvvoltage electrical current. Electrode 42 may be connected to an amplifying system, which in turn is connected to a suitable control for the control of gas flow to the main burner with the amplifier serving to control the energization of the control in accordance with the current flow between electrode 42 and the burner.

With the apparatus of the heating system in the above described igniting device thus installed, the closing of a circuit between the high voltage electrical source and the electrode 3| and the opening of the valve to the pilot burner (which may be done either simultaneously or one shortly after the other) will cause gas to issue from the two orices I3 and I4 and slot I5 at approximately the same time that an arc exists between the end of electrode 3| and the edge of orifice I4. This will cause ignition of the gas issuing from or'ice I4 and the carrying around of the flame thus started through the slot I5 to orifice I3. As soon as the flame from orifice I3 strikes the electrode 42, a closed circuit will be formed from the electrode 42,

through the flame at orifice I3, plate 48, shield 41, the grounded burner |I, the above mentioned amplifier (not shown) and through theA source of electrical energy back to the electrode 42.

While the arc existing between the electrode 3| and the burner may be permitted to continue, it is the general practice in heating systems to provide a switch controlled by an amplifier to break the circuit to the ignition electrode 3| upon the electrode 42 sensing a iiame at orice I3. With the igniting device thus in operation, it is obvious that the main burner may be supplied fuel periodically under the control of a room thermostat, or other control of the system, and be assured of becoming ignited.

to be mounted in any suitable manner' so lthat If for some reason the orifice I3 becomes clogged up, as by the falling of soot onto the top of the burner, or for any other reason that the flame at orifice I3 should become extinguished, the circuit to the amplifier will become broken and thus cause the shutting down of the main burner.

On an inspection of the drawing it is readily seen that the shields 48 and 49 prevent any portion of the flame issuing from oriiice I4 or from slot I5 from contacting the electrode 42, and tends to prevent ions generated by an arc between electrode 3| and orifice I 4 from reaching electrode v42 by grounding said ions. Therefore, even though a flame may exist at orifice I4 when no flame exists at I3, or an arc at electrode 3| may exist', the circuit from the electrode 42 to the grounded burner II through a conducting flame or stream of ions remains broken.

As it is apparent to those skilled in the art that modifications may be made in the above described igniting device without departing from the spirit of the invention therein, it is to be understood that the scope of the invention is to be determined solely from the appended claims.

1. An igniting device comprising a burner having a first orifice for directing a flame in one direction and a second orifice for directing a second ame in another direction at substantially" 'a right angle to said one direction, a runner flame slot extending between said orifices, a bracket extending laterally from and grounded to said burner, an ignition electrode supported by and insulated from said bracket and terminating a short distance from and substantially in alignment with said rst orice, a flame sensing electrode supported by and insulated from said bracket and terminating substantially in alignment with and spaced from said second orifice, and a shield supported by said bracket and having a surface portion positioned transversely between said first orifice and said flame sensing eiectrode so as to prevent a iiame at said first orifice from contacting said sensing electrode but to permit a fiame from said second orifice to contact both said sensing electrode and said shield.

2. In combination, a burner having angularly disposed first and second orifices with a runner slot extending therebetween, an L-shaped ignition electrode positioned with one end thereof in the path of gas flow from said first orifice, an L- shaped fiame sensing electrode positioned with one end thereof in the path of gas flow from said second orifice, and an L-shaped shield of flat material positioned between said electrodes and between said first orifice and said name sensing electrode with the fiat surfaces thereof substantially at right angles to the plane of said electrodes to prevent a flame at said first orifice from impinging on said iiame sensing electrode.

3. In combination, a burner having angularly disposed first and second orices, an ignition electrode having an end thereof positioned in the path of gas flow from said iirst orifice, an L- shaped fiame sensing electrode positioned on the opposite side of said ignition electrode from said burner and having an end thereof in the path of gas flow from said second orifice, anda shield of fiat material positioned between said electrodes and between said first orifice and said fiame sensing electrode with the flat sides thereof extending transversely of the plane of said electrodes to prevent a fiame at said rst orifice from impinging on said fiame sensing electrode.

4. In combination, a burner having angularly disposed first and second orifices, an ignition electrode having an end thereof positioned in the path of gas flow from said first orifice, a fiame sensing electrode positioned on the opposite side of said ignition electrode from said burner and having an end thereof in the path of gas flow from said second orifice, and a shield of fiat material positioned between said electrodes and between said first orifice and said flame sensing electrode with the fiat surfaces thereof extending transversely of the plane of said electrodes to prevent ya name at said first orifice from impinging on said flame sensing electrode.

5. An igniting device comprising a burner having a first orifice and a second orifice and a runner fiame slot extending between said orifices, an ignition electrode terminating a short distance from and substantially in alignment with said first orifice, a flame sensing electrode terminating substantially in alignment with and spaced from said second orifice, and a shield grounded to said burner and positioned between said iirst orifice and said name sensing electrode so as to have a larger surface thereof contacted by fiame than contacts said sensing electrode and so as to prevent that portion of the fiame supported by said first orifice and runner ame slot from contacting said sensing electrode.

6. In combination, a burner having first and second orifices, an ignition electrode having an end portion thereof positioned in the path of gas flow from said first orifice, a fiame sensing electrode having an end portion thereof positioned in the path of gas flow from said second orifice, and a shield of substantially flat material positioned between said electrodes and between said first orifice and said flame sensing electrode with the flat surfaces of an end portion thereof extending transversely between said end portions of said electrodes to prevent a flame at said first orifice and ions from said ignition electrode and first orifice from impinging on said flame sensing electrode.

7. In combination, a burner having first and second orifices with a runner slot extending therebetween, an ignition electrode having an end portion positioned in the path of gas flow from said first orifice, a fiarne sensing electrode having an end portion positioned in the path of gas flow from said second orifice, and a shield of substantially fiat material positioned transversely between said end portions of said electrodes and between said first orifice and said flame sensing electrode to prevent `a flame at said rst orifice from impinging on said flame sensing electrode but to permit a portion of a flame from said second orifice to impinge on said shield.

JAMES W. SMITH.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,304,200 Plein et al Dec. 8, 1942 2,396,146 Atwater Mar. 5, 1946 2,402,763 Longini June 25, 1946 

